Revert "Input: synaptics - allocate 3 slots to keep stability in image sensors"

This reverts commit 63c4fda3

 as it
causes issues with detecting 3-finger taps.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=100481
Cc: stable@vger.kernel.org
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>